{"schemaVersion":1,"slug":"iec-local-isolator-plan-mark","name":"Local isolator plan mark","kind":"symbol","abbreviation":"ISO","aliases":["isolating switch plan mark","rotary isolator","maintenance isolator"],"category":"installation-communications","drawingTypes":["GA"],"referenceFamilies":["IEC"],"summary":"Plan mark for a local isolating switch placed beside fixed equipment for safe maintenance.","description":["Local isolators are placed within sight of motors, air-conditioning units, pumps and fans so maintenance staff can isolate and lock the supply. Plans draw a small switch box with an isolation mark or the letters ISO beside the equipment it serves, sometimes with a lock indication.","The mark tells the installer to provide a device rated for isolation and, where required, lockable in the off position. Pole count follows the supply: three-pole or four-pole for three-phase plant. It does not specify utilisation category or whether the device can switch motor load. Those are in the schedule."],"readingNotes":["Check it is within sight of the equipment.","Confirm pole count and locking provision."],"drawingChecklist":["State poles and rating.","State lockability.","Tag the equipment served."],"distinction":"A switched socket outlet is not an isolator; this plan mark designates an isolation-rated device.","facts":[{"label":"Purpose","value":"Isolation for maintenance"},{"label":"Typical equipment","value":"Fans, pumps, condensers, motors"},{"label":"Exact standard graphic","value":"Not reproduced here; confirm the form against IEC 60617 and the project legend"}],"references":[{"sourceId":"iec-diagrams","relevance":"IEC graphical symbol context; independently drawn here."},{"sourceId":"switching-devices","relevance":"Explains the isolation function and its requirements."}],"related":["switch-disconnector","lockable-switch-disconnector","iec-two-pole-light-switch"],"artwork":"s28-iec-local-isolator-plan-mark","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Isolating switch, installation plan","reference":"IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier."},"plainEnglish":{"title":"What does Local isolator plan mark mean?","introduction":"Local isolators are placed within sight of motors, air-conditioning units, pumps and fans so maintenance staff can isolate and lock the supply. Plans draw a small switch box with an isolation mark or the letters ISO beside the equipment it serves, sometimes with a lock indication.","example":"The mark tells the installer to provide a device rated for isolation and, where required, lockable in the off position. Pole count follows the supply: three-pole or four-pole for three-phase plant. It does not specify utilisation category or whether the device can switch motor load. Those are in the schedule.","drawings":"Check it is within sight of the equipment. Confirm pole count and locking provision. A switched socket outlet is not an isolator; this plan mark designates an isolation-rated device.","terms":[{"name":"Phase","meaning":"One of the related AC waveforms in a power system."},{"name":"Rating","meaning":"A value stating the conditions for which equipment is specified."},{"name":"Schematic","meaning":"A drawing showing function and connections rather than physical appearance."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"IEC graphical symbols for diagrams","url":"https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/"},{"label":"Elementary switching devices","url":"https://www.electrical-installation.org/enwiki/Elementary_switching_devices"}],"detail":"Plan mark for a local isolating switch placed beside fixed equipment for safe maintenance. A switched socket outlet is not an isolator; this plan mark designates an isolation-rated device.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-local-isolator-plan-mark","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-local-isolator-plan-mark.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"iec-diagrams","title":"IEC graphical symbols for diagrams","publisher":"IEC","url":"https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/","type":"standard","scope":"IEC 60617 and related symbol-design publications. Full database access requires a subscription.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"IEC graphical symbol context; independently drawn here."},{"id":"switching-devices","title":"Elementary switching devices","publisher":"Schneider Electric — Electrical Installation Guide","url":"https://www.electrical-installation.org/enwiki/Elementary_switching_devices","type":"manufacturer","scope":"Explains disconnectors, load-break switches, contactors and fuses. The manufacturer diagrams remain at the source.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Explains the isolation function and its requirements."}]}